What are the processes (reactions) that take place to release so much energy in a nuclear power plant?

What must you know about a nuclear reaction to calculate the amount of energy it will produce? A. The product of the total nuclear mass before and after the reaction B. The ratio of total nuclear mass before the reaction to the total nuclear mass after the reaction C. The sum of the total nuclear mass before and after the reaction D. The difference between the total nuclear mass before and after the reaction

Another series of nuclear reactions that can produce energy in the interior of stars is the cycle described below. This cycle is most efficient when the central temperature in a star is above 1.6 × 107 K. Because the temperature at the center of the Sun is only 1.5 × 107 K, the following cycle produces less than 10% of the Sun’s energy. (a) A high-energy proton is absorbed by 12 C. Another nucleus, A , is produced in the reaction, along with a gamma ray. Identify nucleus A decays through positron emission to form nucleus B. (c) Nucleus B absorbs a proton to produce nucleus C and a gamma ray. Identify nucleus C absorbs a proton to produce nucleus D and a gamma ray. Identify nucleus D. (e) Nucleus D decays through positron emission to produce nucleus E. Identify nucleus E. (f) Nucleus E absorbs a proton to produce nucleus F plus an alpha particle. What is nucleus F ? Note: If nucleus F is not 12C—that is, the nucleus you started with—you have made an error and should review the sequence…

B please, help